Water heater for a stock tank



FIG. 1 is a front elevational view of a water heater for a stock tank showing our new design, the rear view being substantially a mirror image thereof.

FIG. 2 is a right side elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a left side elevational view thereof. 

The ornamental design for a water heater for a stock tank, as shown and described. 